Field of the Invention and Related Arm Statement
This invention relates to a video endoscope system having a signal processing means which can respond to different types of imaging means.
Recently, there has come to be extensively used an optical type endoscope provided with an observing optical system wherein an optical image is formed on the entrance end surface of an image guide by an objective arranged on the tip side of an elongated insertable part and is transmitted to the exit end surface arranged on the eyepiece side through this image guide.
Also, recently, there has been practiced an electronic type endoscope provided with an imaging means whereby an optical image is formed on the imaging surface of a solid state imaging device by an objective without using an image guide and is photoelectrically converted by this solid state imaging device.
Also, a television camera having a built-in imaging means is fitted to the eyepiece part of the above mentioned optical type endoscope so as to color-display the image.
The solid state imaging device forming the above mentioned imaging means has preferably many picture elements from the viewpoint of the resolution. However, in case the solid state imaging device is contained in the tip part of the insertable part inserted into a body cavity, the imaging device must be small.
As the outside diameter of the insertable part is different depending on the uses, the number of picture elements (or pixels) of the solid state imaging device to be fitted may be different.
Further, even if the number of picture elements is the same, due to the dispersion or improvement of the solid state imaging device, such spectral characteristic as the sensitivity may be different.
Therefore, in U.S. Pat. No. 4,667,229, an output signal level adjusting means or displaying position dispersion adjusting means is provided so that the output signal level may be identical even for a different type solid state imaging device.
However, the above mentioned U.S. patent can not respond to the case of a different number of picture elements.